Alcoa of Australia Residue ManagementResidue DustThe main source of potential dust within Alcoa of Australia’s refineries is the residue drying areas. Dust generated in these areas mostly consists of fine clay particles and sodium carbonate crystals. Alcoa of Australia employs a complex system of residue dust management tools to attempt to minimise dust generation and keep any dust within Alcoa property.

Our dust management systems consist of a range of both proactive and reactive strategies. Dust control management plans are constantly reviewed and progress is tracked in weekly review meetings.

Each site has a dust monitoring system in accordance with its licence requirements. This typically requires daily dust levels to be measured in key locations around our residue areas. The monitors are located strategically and the positioning takes into account our proximity to neighbouring communities. In addition, Alcoa of Australia uses separate dust monitors to monitor dust emissions from our residue areas continuously in order to gauge the effectiveness of our dust management measures.

In order to maintain preparedness to deal with weather conditions which could impact on our dust management practices (high wind can pick up dust particles), we receive daily weather forecasts for the following three day period. They include a ‘Dust Risk Rating’ covering rain, wind speed and wind direction. This helps us deploy strategies to deal with dust prone areas well before strong winds arrive. For example, experience has shown that by pre-wetting the residue areas prior to strong winds, it significantly reduces the potential for dust generation.

Apart from the use of sprinklers already described, following are examples of other dust management techniques by Alcoa of Australia to minimise dust generation:

Turning over the mud in the residue areas;

Spraying exposed banks with bitumen;

Applying aggregate to large areas not required in the short term; and

Planting grasses or other vegetation on embankments to prevent dust generation.

It is important to note that health risk assessments and air monitoring around our operations show no cause for concern in connection with residue dust. For more in relation to health visit: www.alcoa.com.au/healthandwellbeing.